Apparatus for dispersing liquids in a spray or fog



March 15, 196 R. E. STEVENS 3,239,950

APPARATUS FOR DISPERSING LIQUIDS IN A SPRAY OR FOG Filed Dec. 5, 1962 5 Sheets-Sheet l INVENTOR. ROBERT E. STEVENS ATTORNEYS March 15, 1966 R. E. STEVENS 3,239,960

N A SPRAY OR FOG APPARATUS FOR DISPERSING LIQUIDS 3 Sheets-Sheet 2 Filed Dec. 5, 1962 INVENTOR.

ROBERT E. STEVENS ATTORNEYS March 15, 1966 R. E. STEVENS APPARATUS FOR DISPERSING LIQUIDS IN A SPRAY OR FOG 3 Sheets-Sheet 3 Filed Dec.

J R 3 mm Rm m W W N N E w R i m T m a B2 w win}? 3 m m E. m mi xmozimz m mm m 0 M L? o zom.6m w Q E M N2 0 r wk mozmmzww EwwEm m lk United States Patent C) 3,239,960 APPARATUS FOR DISPERSING LIQUKDS IN A SPRAY (1 R FOG Robert E. Stevens, Westtield, Inch, assignor to Cnrtrs Dyna-Products Corporation, a corporation of Ohio Filed Dec. 3, 1962, Ser. No. 241,867 8 Claims. (Cl. 43l29) This invention relates to apparatus for creating a spray or a fog of liquid which is to be dispersed in particle form over a substantially wide area, as for example, in dispersing of liquid insecticides.

Apparatus of this type is often required to produce a spray (or a fog) intended to cover a substantially great area. To accomplish this purpose properly, it is necessary to break the liquid into particles of substantially uniform and small size, and to distribute such particles evenly over the area. When a large area is to be covered, the amount of liquid to be handled in this matter is substantial, and it is desirable to provide apparatus which can be operated without requiring substantial maintenance or skill in its use, while being capable of handling the high rates of liquid consumption which are necessary for this purpose.

For example, the present invention provides a. device which can create either a spray (i.e., small particles in air) or a fog (a suspension of fine condensate droplets in a gas) while dispersing liquid insecticide solutions at rates of as much as 120 gallons per hour. On the other hand this rate can be substantially decreased, if the requirements of a job are such that a much lower rate is necessary, without varying the particle size and even particle distribution obtained by the apparatus. In creating fogs, particularly, the velocity of gases through the fogging apparatus may be in the neighborhood of 250 feet per second, at volumes up to 1,000 c.f.m., and at temperatures sufiicient to vaporize the liquid completely, for example temperatures in excess of 1,000 F. and in the neighborhood of 1,850 P. While operating at such temperatures and rates, the apparatus must still avoid formation of carbon in the fogging nozzle in order to minimize maintenance problems.

Furthermore, since many of the carrier liquids for insecticides are flammable, it is necessary to provide a supply of hot gas, for example at the rates and temperatures mentioned above, while avoiding the introduction of tlame into the fogging nozzle Where the insecticide solution might ignite.

Accordingly, the primary object of the present invention is to provide a novel apparatus for creating sprays or fogs for the purpose of distributing liquids as small particles of essentially uniform size.

Another object of the invention is to provide a novel high capacity apparatus for producing a thermal aerosol fog from a liquid solution or formulation.

A further object of the invention is to provide such an apparatus which is completely independent in its operation, and may be mounted, for example, upon a truck or trailer and operated in remote areas away from power supply.

Another object of the invention is to provide such a novel apparatus for producing sprays or fogs, incorporating automatic controls which assure safe operation of the apparatus without requiring special skill for its operation.

An additional object of the invention is to provide a novel nozzle construction for spraying and also particularly for creating thermal aerosol fogs at high capacity.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a perspective view showing the overall arrangement of the apparatus provided by the invention, and showing schematically its connection to a spray tank of liquid solution to be dispersed in particle form;

FIG. 2 is a side view of the apparatus shown in FIG. 1, as viewed from the back side of the apparatus as it appears in FIG. 1;

FIG. 3 is an enlarged detailed view, partly in section and with some parts in elevation and broken away, showing details of the hot gas generating device and the novel nozzle construction provided by the invention;

FIG. 4 is a detail view of the mounting for the nozzle battle; and

FIG. 5 is a circuit diagram showing the controls for the apparatus.

Referring to the drawings, and particularly to FIGS. 1 and 2, the apparatus is supported on a base 10, and includes an internal combustion engine 12 connected through suitable means (such as drive belts, not shown) to drive a blower 15. The blower has an outlet duct 16 which leads to a combustion chamber 20, in which the air supplied by the blower may be heated, if desired in the production of thermal aersol fogs by the apparatus. The combustion chamber has a hot gas supply outlet 22 on which there is mounted a fogging nozzle 25. The liquid to be sprayed or dispersed in a fog is supplied to the nozzle 25 to a T fitting 27 from a pair of supply lines 23 and 29. These lines lead through solenoid controlled valves 3% and 32 to a supply T fitting 34 which is connected to receive the liquid formulation, such as an insecticide-oil solution, from a supply pump 35. This pump is driven by an electric motor 37. The pump is provided with an inlet line 4t) having a suitable filter 42 on the end thereof which is adapted to be immersed in a tank of the solution, shown schematically at 44. The pump also is provided on its outlet side, preferably upstream of the supply T 34, with a relief valve 45 which can return oil supplied by the pump above a set pressure, through a return line 46 into the tank 44.

The combustion chamber 20 is of a special construction designed to burn fuel at relatively high rates and thus to provide relatively great quantities of hot gas at substantially high velocities. The combustion chamber is used for this purpose, however, only when the apparatus is functioning to produce thermal aerosol fogs, and When the apparatus functions as a high capacity sprayer then there is no combustion in chamber 2% .and the high velocity air from blower 1L5 merely passes through the combustion chamber and its gas supply outlet 2Q. Accordingly, details of the combustion chamber are explained later in this specification.

On the gas supply outlet 22 there is a mounting flange 50, and to this flange is attached a novel nozzle construction which is designated by the general reference numeral 25. This nozzle includes an outer nozzle tube 52 and an inner nozzle tube 55 which is shorter in length than the outer tube, and thus has its terminal end 56 spaced a substantial distance inwardly from the discharge end 57 of the outer tube 52. The inner tube extends in spaced relation to the walls of the outer tube, and preferably coaxially therewith, such that the gas passing from the combustion chamber outlet 22 is divided into separate streams, one stream flowing through the annular space 60 between the tubes, and the other stream flowing through the inner tube 55. A simple and effective mounting of the inner tube can be obtained by forming a number of turned out tabs 62. thereon to engage with the walls of the outer tube 52 at a plurality of locations (for example three equally spaced) about the opposite ends of the inner tube. These tabs can then be secured, as by welding, to the outer tube 52.

A relatively short distance beyond the entrance end of the nozzle, i.e., that end which is fastened to flange there is a spray means in the form of a nozzle 65 mounted on an L connection -66 which in turn is positioned on a short length of pipe 67 fastened to the nozzle by a fitting, or cap 68. Thus, the nozzle 65 is positioned approximately centrally of the inner tube and pointed in a downstream direction to direct a spray of fluid to be dispersed into the high velocity stream of gas passing through the inner tube 55. It should be noted that when the device is employed as a thermal aerosol fog generator it is desirable to have an indication of the temperature at the entrance to the nozzle, and for this purpose a thermocouple 70 preferably is mounted in the wall of the outer nozzle tube 52, immediately upstream of the spray head 65.

Downstream of the spray head, and spaced upstream somewhat from the terminal edge 56 of the inner tube, is a circular baflle member 75 which is mounted on a plurality of support rods 76. Details of this mounting are shown in FIG. 4, and may comprise merely a number of rods fastened at their inner ends to the baffle and secured to the tube 55 by staking as indicated at '77.

When the device is operating high velocity gas is supplied through the combustion chamber outlet 22, the outer gas stream flows through the space at while the inner or central gas stream flows through the inner nozzle tube 55 and around the spray head 65 and baflle 75, and rejoins the outer stream beyond the end 56 of the inner nozzle tube, in the region or zone within the discharge end of the outer tube, designated by the general reference numeral 80. The velocity of the inner stream is reduced by cont-rolling the space between the baffle and the Walls of the inner nozzle tube, and this prevents collapsing of the spray cone created by the spray head 65. The baffle 75 likewise is shaped to increase divergence of the spray coneand further prevents collapse of the spray cone of liquid particles, and thus prevents a concentration of such particles toward the center of the stream.

The outer stream of gas flowing through the space 60 tends to converge after passing the end of the inner tube. Thus the converging outer stream and the diverging inner stream, which is laden with liquid particles, rejoin to create a violently turbulent zone in the region designated 80. Since larger liquid particles tend to collect on the inner surface of tube 55 and on the surface of baffle '75, the sharp edges of the tube 55 at its terminal end 56, and the sharp edges around the baffle 75, allow a thin cylindrical sheet of liquid to be pulled from the edges of the tube 55 and of the bafile by the high velocity gas passing over these surfaces. This cylindrical sheet of liquid is immediately broken down into small particles which enter the turbulent zone or region 80. Smaller particles created at the spray head 65, having less mass, tend to be carried directly through the annular space between tube 55 and baffle '75, and on into the tu-rbulent zone. Since both gas streams assume approximately the same velocity before discharging from the outer tube 52, recombination of small particles is substantially nil, and the dispersion of substantially uniform particles is maintained over the cross sectional area at the discharge end 57 of the outer nozzle tube.

Due to the action of the air streams as just described, causing breaking up into small particles the liquid issuing from the spray head 65, there is no need for this spray head to be of a high pressure, small orifice type. The head merely distributes evenly the incoming liquid into the'gas stream within tube 55, and larger openings in the spray head 65, for example openings of about up to onequarter of an inch in diameter can be used. This feature is of particular significance when the apparatus is used as a thermal aerosol fog generator, as will be pointed out.

The combustion chamber 20 is, basically, a high pressure type oil burner. It differs, however, from the normal configuration of suchburners in thatthe blower 15 is a centrifugal blower rather than the axial flow (squirrel cage) type normally used with conventional high pressure oil burners which operate at maximum air pressures of around 0.2 to 0.3 inch of water in their combustion chamber. In the present construction, in order to attain desired gas velocities in the neighborhood of 250 feet per second, and at the volumes required which are up to 1,000 c.f.m., it is necessary to fi-re the burner at combustion chamber pressures as high as twelve inches of water, and these pressures are attained by using a centrifugal type blower.

When providing air at these rates, and under these pressures, other conditions are created which must be considered in the design of the combustion chamber. The high velocity air stream tends to colltpse the spray cone of oil from the oil nozzle or gun (FIG. 3), and the particles of fuel oil tend to be accelerated to a speed at which flame would not progress and bring about full ignition of the oil spray. Therefore, baffles and 92 are mounted directly downstream of the spray nozzle 85 and function to divert a portion of the air stream entering the chamber through the blower outlet ducts 16 and to present a barrier (particularly the bafille 92) which causes the stream of air to spread out over a much larger area, with a net result of reducing the velocity of the air. Bathe 92 becomes heated to such an extent that it helps to support an even and complete ignition of the fuel air stream in the upstream or initial section of the combustion chamber. Each of the baflies is of relatively thin sheet metal having stiffening ribs 93 of generally V-shape in cross-section, as appears on baffle 90.

The oil spray nozzle 85 and the ignition spark electrodes 95 are moved farther forward out of the blower outlet tube 16 than in normal oil burner practice, and the ends of the electrodes are supported somewhat farther forward from the spray nozzle 85 than in normal practice. Ordinarily, in a conventional oil burner construction, this would cause formation of carbon on the electrodes and the nozzle, but since the outer diameter of baflle 90 is very close to the inner diameter of the inner chamber wall 98, no combustion occurs upstream of baffle 90, and carbon does not form on the nozzle or the electrodes, the temperature at the oil spray nozzle 85 normally being held below 25 0 F.

Bafiles and 102 are mounted in the combustion chamber downstream of baffle 92 and function to cause the gases, and particularly the burning. fuel-air mixture, to follow an intricate and tortuous path through the combustion chamber. This in effect lengthens the flow path within the combustion chamber as well as causing thorough mixing of the combustible fuel-air mixture to assure complete combustion before the gases reach the hot gas supply outlet 22.

Many types of liquids used in the production of thermal aerosol'fogs will be combustible, or at least include a combustible ingredient. It is, therefore, necessary to assure that the flame does not reach through the hot gas supply outlet 22 to cause ignition of the liquid being.

sprayed into the nozzle 25 through the spray head 65.

The hot high velocity gases thus flowing, in separate streams, through the nozzle construction 25 cause the particles of liquid sprayed through the spray head 65 to vaporize and to be discharged from the nozzle 25 into the surrounding atmosphere where the vapor is condensed into a fog composed of liquid particles of substantially uniform size and essentially uniform distribution. The flow of hot gas through the annular space 60 in the fogging nozzle helps to keep the walls of the internal nozzle tube 55 at a relatively high temperature and thus assists in vaporizing any larger liquid particles which might collect on the inner surface of tube 52. This assures that complete vaporization can take place readily when the film resulting from deposition of such larger particles on the wall of tube 55 is swept from the sharp edge of the terminal edge 56 into the turbulent zone or region 80.

Since the transfer of heat to small particles is more rapid and eflicient, the fogging nozzle constructed as shown and described herein is capable of producing small particles at higher rates and at temperatures below that temperature which causes oxidation of the liquid formulation (such as oil or oil solution) which is sprayed through the head 65 and can cause carbon formation. Therefore, the elimination of carbon formation and the need for cleaning the nozzle is accomplished.

Another important aspect of the invention is the provision of a high capacity spraying or fogging device which is self-contained, requires no specially trained operator, and incorporates proven controls with which many persons are familiar. For example, the engine 12 may be a conventional air-cooled single cylinder internal combustion engine of conventional construction. It is provided with its own fuel tank 112 (FIG. 2) of sufficient capacity, for example, to permit several hours of operation of the device. This engine is connected through suitable drives, such as the belt and pulley drives shown generally at 115 in FIGS. 1 and 2, to rotate the blower and also to drive a 110 volt A.C. electric generator 117. This generator, as will be explained, provides power during operation of the device for the various controls.

Driven from the same shaft as the blower 15 is a fuel pump 120 which draws fuel oil through a conventional filter 121 from the fuel oil tank 122. The ignition transformer 124, capable of operation from a 110 volt A.C. circuit, is mounted on top of the blower housing as shown particularly in FIGS. 1 and 3, and is of a conventional type, well known in the oil burner art. The control circuits, are for the most part, contained within a suitable housing 125 mounted at the rear of the base 16, and the control of the device can be exercised through a movable control station or console 13-19, details of which are explained hereafter, which is connected to the control box 125 through a cable 132.

FIG. 5 illustrates a suitable control circuit with portions of the aforementioned apparatus shown schematically to illustrate their connection in the control circuit. The engine 12 is provided with a conventional electric starter 135 which can be energized through a battery 136 under control of a starter relay 138. Connections of the generator 117, the burner electrodes 95 and transformer 124, and of the fogging or spraying liquid pump 35, its electric drive motor 37, and the solenoid operated valves and 32 likewise are shown in FIG. 5.

The overall control of the apparatus is achieved through a seven-position six-level gang switch 141) which is shown schematically in FIG. 5. This switch includes the manually rotatable control handle 141, which may include detents to hold the switch in any of its seven positions, and movement of this handle produces like concurrent movement of the wipers in the six levels of this switch, designated respectively 140a through 1407. With the switch in the position shown, there is a direct ground circuit through the wiper of level Mild to the ground contact 142 on the magneto (not shown) of the engine 12. This prevents the engine from starting and thus prevents any operation of the apparatus since all power is obtained from the engine.

When the switch 140 is moved to its second position, the Wiper of level 140a will complete a preparatory starting circuit from battery 136 to the starting push button switch 145. When this switch is closed, the circuit is completed to energize the starting relay 138 and the engine starter 135 receives power from the battery. At the same time, the ground circuit to the magneto ground is broken by movement of the wiper in level 140:! to its second contact. The magneto ground circuit is normally open (ex- The engine 12 starts with switch 14-0 in its second position, and this, of course, causes the blower 15 to operate and operates the generator 117 and the fuel pump 120. Flow of fuel oil to the burner nozzle is blocked, however, by the normally closed solenoid valve 150 which is connected in the fuel oil line downstream of pump 120, and is not at this time energized. Assuming that the engine continues to run, release of the starting switch 145 will deenergiz/e the starter relay 138 and open the circuit between the engine starter and battery 136.

The operator can then move switch to its third position. This moves the wiper in level 140a to an open contact and avoids the possibility that the engine starter could be actuated if the starting switch were later closed accidentally. As noted, in the third position the wiper of level 14th! is on an open contact.

With the generator operating, there is an electrical power supply across its output lines G1 and G2. In a preferred system, the generator supplies 110 volt A.C. A circuit is completed through a recording timer 153 which continues to run whenever the generator is operating to record elapsed operating time of the unit. A circuit is also completed from line G2 through the contact in the third position of switch level 14%, and through its wiper to line 155 which leads to the fog oil pump motor 37, and thus this motor begins to run. Both of the solenoid operated valves 31) and 32 will at this time be deenergized, and the output of the fog oil pump 35 passes through its relief valve 45 and back to tank 44. There is, however, supply of fog oil under predetermined pressure in the supply lines 28 and 29. It will be noted also that the wiper in switch level 1411b completes the circuit to line 155 in all its subsequent contact positions.

The following explanation of the circuit assumes that the apparatus is being used to generate a thermal aerosol fog, and that it is desired to initiate combustion of fuel in the combustion chamber 211. Accord-in ly, when switch 140 is moved to its fourth contact position a circuit is completed through the wiper of switch level 1411c from the generator line G2, through a fog or spray switch 164 which is normally closed (and thus in the fog position) to a power supply circuit line 162. This line supplies power to a conventional burner controller 165, certain details of which are shown within the dotted outline in FIG. 5.

It should be understood that this is a conventional controller used, for example, to operate many types of pressure oil burners, and that the necessary details of the controller are described herein merely for purposes of providing a full explanation. Accordingly, the .relay coils and their corresponding contacts within the controllers are illustrated in a somewhat different fashion than the other relays and corresponding contacts in the circuit diagram. The other power line to the controller is through a connection to the generator line G1, as shown.

When the circuit has completed to line 162, this energizes the primary of the controller transformer T1 and this transformer in turn supplies power to the electronic relay network shown schematically at 166. One control input to this network is through line 163 from a flame detector photocell 170 (FIGS. 3 and 5) which is mounted in the blower outlet duct 16 facing toward the combustion chamber. When ignition occurs and there is a flame in the combustion chamber, there is a corresponding signal output from the photocell 170 through line 168 to the network 166, where this signal is amplified and utilized to control energization of the flame relay FR. This relay has normally closed contacts PR1 in the low voltage part of the controller circuit, and normally open contacts PR2 in the main line portion of the controller. The flame relay also has normally open contacts PR3 also in the main line control part of the controller.

The low voltage section of controller 165 includes a check relay CR connected across the secondary winding of transformer T2. The primary Winding of this transformer is connected between line G1 and the contacts a PR3, in addition to others. Also in the low voltage circuit, in series with the contacts PR1, is a safety switch comprising a thermal control including a heater coil SSH arranged to open the normally closed contacts SS1 (mounted, for instance, on a bimetal next to the heater) when a predetermined time has elapsed after power is applied to the heater. The contacts SS1 control the supply of power to the operating coil LR of a load relay which has normally open contacts LR1, connected in shunt across theheater SSH and contacts PR1, and normally open contacts LR2 which are in series with the contacts PR2.

Briefly, when switch 140 is moved to its fourth position and the circuit is completed through the wiper of level 14tlc, as just described, this of course completes the supply circuit to transformer T1. The flame relay PR is energized by the network 166 and contacts PR2 and PR3 close, while contacts PR1 open. It will be noted that the supply line 162 has a branch which connects in common to each of the contacts LR2, CR1 and PR3. At this time power is supplied through PR3 to the transformer T2, and check relay CR is energized to cause closing of contact CR1. At the same time, a control voltage is applied through the secondary winding T212 to the electronic network 166 causing the flame relay PR to be deenergized, thus again closing PR1 and opening PR2 and PR3. The check relay holds the power on transformer T2 through its now closed contact CR1.

Closing of PR1 completes a circuit through the heater SSH and the closed contacts SS1 through the load relay coil LR and this in turn closes contacts LR1 and LR2. Contacts LR1 act as holding contacts to maintain the power supply to the relay coil LR. The circuit from line 162 through the now closed contacts LR2 completes a connection from the generator line G2 through a starter line 171 which leads to the ignition transformer 124 and to the burner oil valve 159. This valve is opened. and power is supplied through the ignition transformer to the electrodes 95. If combustion is initiated within a predetermined time, the photocell 17% will sense the light from the flame and a signal will pass through line 168 to the network 166 causing the relay PR again to be energized. In the meantime, the heater SSH is being supplied with power, and it will open its contacts SS1 to drop out relay LR if the signal from the photocell 170 does not first occur. If LR drops out, the contacts LR1 and LR2 will open and. cut off the power to the ignition transformer of the oil valve 1511.

Assuming that ignition is completed, the relay PR is energized, opening contacts PR1 to take the safety switch heater SSH out of the circuit, and contacts PR2 and PR3 close. Closing of contact PR2 completes a supply circuit from the now closed contacts LR2 to a line 172 which leads to the fifth and seventh contacts of switch level 146e, into the sixth and seventh contacts of switch level 140]. Line 172 also supplies power to a line 173 which completes a circuit through a protector relay having a coil PR and a pair of double throw contacts PR1 and PR2 which are normally in the position shown when the relay is deenergized. Thus, contact PR1 supplies a ground connection to line 174 leading to the fifth, sixth and seventh contacts of switch level 14M. When switch 140 is in any of these positions, if the protector relay is deenergized, a ground circuit will be completed through PR1 and the wiper of switch level 141M to the magneto ground 142, stopping the engine 12.

The common connection of relay contact PR2 is in circuit with the line 162, and thus when relay PR is deenergized, PR2 completes a circuit from line 162 (which leads back to G2 through 1400 in the fourth, fifth, sixth and seventh positions of switch 140) and a line 175 which extends through a warning lamp 177 to the generator line G1. When the protector relay is energized, this lamp is therefore extinguished. Assuming that ignition has been accomplished in the combustion chamber, the controller circuit 165 will make the connections previously described and the protector relay will be energized, such that the engine will continue to run and the warning light 177 will be extinguished.

The operator then has the choice of moving switch 14% to the fifth, sixth, or seventh positions. In the fifth position a circuit is completed through line 1st), which leads back to line 172 and the controller, and through it to line G2 through switch level 14 3c. The wiper in switch level Mite is connected to solenoid valve 30, and thus in the fifth position this solenoid will be energized to open the valve and supply fogging formulation to spray head in the fogging nozzle at a predetermined lower rate. At the same time, a circuit is completed through a lamp 182 which informs the operator that only the low rate fogging control valve is open.

Similarly, moving switch to its sixth position completes a circuit from line 1813 through the wiper in level 14% to a line 135 which supplies power to the solenoid valve 32, causing it to open while the solenoid valve 34) has been deenergized. and closed. This will supply formulation to the fogging nozzle at an intermediate rate, and likewise lamp 186 is energized to indicate this condition. Finally, with the switch 149 in its seventh position, power is supplied to both lines 181 and 185 and both valves 30 and 32 are open to supply formulation at the highest rate. Both lights 182 and 186 are energized at this time.

If it is desired to use the apparatus as a variable rate sprayer, rather than producing a thermal aerosol fog, then switch is operated to break the circuit between switch level 1400 in line 162 and to complete a circuit from the generator line G2 to line 180. This cuts off any supply of power through the main controller 165 and the fuel oil valve 150 remains closed and the controller 165 is not operative. However, the protector relay receives power through line 173 to break the ground connection through PR1 to the engine magneto ground. Since there is no power connection to line 162 relay contact PR2 is effectively out of the circuit. However, there is a direct power supply circuit established from G2 through 180 through the switch levels 140a and 140f, permitting the operator to manipulate switch 140 in its fifth, sixth or seventh positions and thus to control the solenoid operated valves 30 and 32 as previously explained.

When operating as a fogging device, if at any time there is a flame-out in the combustion chamber, this will be immediately sensed by the photocell and the flame relay will be deenergized to open contacts PR2 and PR3 and close contacts PR1. The unit will attempt to reignite, but if a flame is not established within the time lapse of the safety switch, the heater SSH will open its contacts SS1 and the entire unit will shut down, since contacts LR2 will open and cut off the power supply to the burner oil valve 150 into the line 172 which in turn controls power to line 173 and 180. The protector relay will drop out and establish a ground connection to the magneto ground to stop engine 12, and since power is cut off to line 186 both of the solenoid valves 30 and 32 will be cut off from power and will close. It is then necessary for the operator to return the switch 140 to its first position and start the entire apparaus over, while determining what was the cause of the malfunction. The thermocouple 70 is connected directly to a temperature gauge 1%, as shown in FIG. 5, and merely provides on the control console a direct indication of temperature at the entrance end of the fogging nozzle 25.

From the above description, it will be apparent that the present invention provides a novel high capacity spraying and/ or fogging apparatus which is completely selfcontained and self-powered and which is readily operated by unskilled personnel. The blower provides air as sufiiciently high velocity and volume to assure that there is an excess of air in the combustion chamber beyond that amount of air required for complete combustion of all of the fuel supplied to the combustion chamber. In other words, there is a predetermined correlation between the supply of fuel and air which assures that the fuel is completely burned Within the combustion chamber, and the baffles provided assist in this regard, thereby forming a high velocity source of hot gases in which there is no flame present. These hot gases assure complete vaporization of the fogging formulation, and due to their high velocity expel from the nozzle at a rate sufficient to carry the resultant fog over a wide area.

In addition, by shutting otf the supply of fuel to the combustion chamber, the device may be used as a high velocity sprayer for dispersing liquid droplets in a stream of air, and the rate of spraying may be adjusted in the same manner as the rate of fogging. The apparatus has other desirable features such as, for example, the fact that it has heat capacity sufiicient to function as a con venient outdoor heater if such is desired, and the electrical power supplied by the generator can be used to run portable tools or the like, for example if an auxiliary power source should be needed in an emergency. The burner controls, as mentioned, are of conventional, Well known and proven design, and are readily maintained or replaced. The entire unit can be mounted on a truck or trailer for mobility, and functions completely independent of exterior power requirements, as explained previously.

While the'form of apparatus herein described constitutes preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A nozzle construction for obtaining a thorough dispersion of particles of a liquid to be spread over a wide area, comprising means providing a supply of high velocity gas, an outer nozzle tube having an entrance end and a discharge end, an inner nozzle tube extending within said outer tube in spaced relation to the interior thereof and having a terminal end substantially short of said discharge end of said outer tube defining a gas mixing zone within said outer tube beyond said terminal end of said inner tube, means mounting said nozzle tubes on said gas supply means to convey the high velocity gas in separate streams through said inner tube and between said tubes, means causing such streams to combine beyond said terminal end of said inner tube to create turbulence in said gas mixing zone of said outer tube within its discharge end, and spray means mounted within said inner tube substantially upstream of said terminal end thereof for introducing a spray of the liquid to be dispegsed into the stream of gas flowing through said inner tu e.

2. A nozzle construction for obtaining a thorough dispersion of substantially uniform particles of a liquid to be spread over a wide area, comprising means providing a supply of high velocity gas, an outer nozzle tube having an entrance end and a discharge end, an inner nozzle tube extending within said outer tube in spaced relation to the interior thereof and terminating in a sharp edged end substantially short of said discharge end of said outer tube, means mounting said nozzle tubes on said gas supply means to convey the high velocity gas through said inner tube as well as between said tubes, baffie means extending across said inner tube upstream of said sharp edged end thereof and arranged to create a turbulent zone of gases within said outer tube between its discharge end and said sharp edged end of said inner tube, and spray means mounted within said inner tube substantially upstream of said bafile means for introducing a spray of the liquid to be dispersed into the flow of gas through said inner tube.

3. A nozzle construction for obtaining a thorough dispersion of substantially uniform particles of a liquid to be spread over a wide area, comprising means providing a supply of high velocity gas, an outer nozzle tube having an entrance end and a discharge end, an inner nozzle tube extending coaxially Within said outer tube in spaced relation to the interior thereof and terminating in a sharp edged end substantially short of said discharge end of said outer tube, means mounting said nozzle tubes on said gas supply means to convey the high velocity gas in separate streams through said inner tube and between said tubes, baflle means extending across said inner tube upstream of said' sharp edged end and arranged to direct the gases flowing through said inner tube across said sharp edged end of said inner tube, and spray means mounted within said inner tube substantially upstream of said baffle means for introducing a spray of the liquid to be dispersed into the stream of gas flowing through said inner tube, said streams combining in said discharge end of said outer tube beyond said sharp edged end of said inner tube to create a turbulent zone in which particles of the liquid are thoroughly and essentially uniformly mixed in the gas.

4. A nozzle construction for obtaining rapid and complete vaporization of a liquid in a. high velocity gas flow to produce large quantities of fog having substantially uniformly sized particles of the liquid therein, comprising means providing a supply of high velocity gas at a relatively great flow rate and at temperatures substantially in excess of 1,00() R, an outer nozzle tube having an entrance end and a discharge end, an inner nozzle tube extending within said outer tube in spaced relation to the interior thereof and having a terminal end substantially short of the discharge end of said outer tube defining a gas mixing zone within said outer tube beyond said terminal end of said inner tube, means mounting said tubes on said gas supply means to convey the hot high velocity gas through said inner tube and also between said tubes to maintain the walls of said inner tube at a substantially high temperature, the flow of gases between said tubes combining with the flow of gases through said inner tube to create turbulence in said gas mixing zone of said outer tube, and spray means mounted within said inner tube substantially upstream of its said terminal end for introducing liquid to be dispersed in a fog from said nozzle.

5. A nozzle construction for obtaining rapid and complete vaporization of a liquid to disperse it in a high velocity gas for producing large quantities of fog, com.- prising means providing a supply of high, velocity gas at a relatively large flow rate and at temperatures in excess of 1,000 R, an outer nozzle tube having an entrance end and a discharge end, an inner nozzle tube extending within said outer tube in spaced relation to the interior thereof and having a terminal end located within said outer tube and substantially short of the discharge end of said outer tube, means mounting said tubes on said gas supply means to convey the hot high velocity gas through said inner tube and also between said tubes to maintain the walls of said inner tube at a substantially high temperature, means causing the flow of gases between said tubes to combine with the flow of gases through said inner tube to create a turbulent zone in that portion of said outer tube between its discharge end and said terminal end of said inner tube including baffie means in said inner tube extending across the center thereof to direct flow of gases outward toward said terminal end, and spray means mounted within said inner tube substantially upstream of said baffle means for introducing a spray of liquid to be dispersed in a fog from said nozzle.

6. A self-contained fog generating and spraying apparatus comprising a blower having an outlet duct, a motor connected to drive said blower, a combustion chamber connected to receive the high velocity air flow from said blower during operation thereof, selectively operable means for supplying fuel into said combustion chamber, ignition means in said combustion chamber adapted to ignite the combustible fuel-air mixture therein, baflle means mounted within said combustion chamber providing a tortuous flow path therein assuring complete combustion prior to exiting of the products of combustion from said chamber to avoid passage of flame from said chamber, means forming a hot gas supply outlet on said chamber, a fogging nozzle connected to receive the hot gas from said supply outlet and including coaxially arranged outer and inner tubes operating to divide the flow of hot gas into separate streams, the outer said nozzle tube extending beyond said inner nozzle tube to form a zone of turbulence within the end of said nozzle where the stream of hot gases flowing between said tubes combines with the stream of gases flowing through the inner tube, spray means mounted within said inner tube substantially upstream from said turbulent zone, and a power operated pump means connected to supply liquid to be dispersed to said spray means for spraying of the liquid into the stream of hot gases flowing through said inner tube.

7. A fog generating and spraying apparatus as defined in claim 6, wherein said means for supplying fuel and said blower are correlated to provide a predetermined fuel-air mixture inwhich there is an excess of air in said combustion chamber over the amount of air required for complete combustion of the fuel supplied.

8. In fog generating and spraying apparatus as defined in claim 6, a safety control circuit including controls governing the operation of said blower and said means for supplying fuel and said spray means, and a device responsive to failure of combustion in said combustion chamber and incorporated in said control circuit to terminate operation of said fuel supply means and said spray means automatically in response to failure of combustion in said chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,901,806 3/1933 Fulton 239-432 2,029,141 1/1936 Warner 239-424 X 2,358,386 9/1944 Doll 239-590 X 2,510,395 6/1950 Goodrie 239-432 X 2,513,417 7/1950 Lindsay 239-432 2,547,018 4/1951 Kucher 239590 X 2,634,805 4/1953 Bills et al. 23977 2,661,239 12/1953 Tirrell 239-77 2,857,332 10/1958 Tenney et a1 239-129 X 2,863,700 12/1958 Ziemke 239-426 2,926,455 3/1960 Morris 43-129 2,926,855 3/1960 Durr 239-129 2,991,944 7/1961 Sullivan 239-304 3,050,262 8/1962 Curtis 239-432 X SAMUEL KOREN, Primary Examiner. v R. A. OLEARY, ABRAHAM G. STONE, Examiners. 

1. A NOZZLE CONSTRUCTION FOR OBTAINING A THROUGH DISPERSION OF PARTICLES OF A LIQUID TO BE SPREAD OVER A WIDE AREA, COMPRISING MEANS PROVIDING A SUPPLY OF HIGH VELOCITY GAS, AN OUTER NOZZLE TUBE HAVING AN ENTRANCE END AND A DISCHARGE END, AN INNER NOZZLE TUBE EXTENDING WITHIN SAID OUTER TUBE IN SPACED RELATION TO THE INTERIOR THEREOF AND HAVING A TERMINAL END SUBSTANTIALLY SHORT OF SAID DISCHARGE END OF SAID OUTER TUBE DEFINING A GAS MIXING ZONE WITHIN SAID OUTER TUBE BEYOND SAID TERMINAL END OF SAID INNER TUBE, MEANS MOUNTING SAID NOZZLE TUBES ON SAID GAS SUPPLY MEANS TO CONVEY THE HIGH VELOCITY GAS IN SEPARATE STREAMS THROUGH SAID INNER TUBE AND BETWEEN SAID TUBES, MEANS CAUSING SUCH STREAMS TO COMBINE BEYOND SAID TERMINAL END OF SAID INNER TUBE TO CREATE TURBULENCE IN SAID GAS MIXING ZONE OF SAID OUTER TUBE WITHIN ITS DISCHARGE END, AND SPRAY MEANS MOUNTED WITHIN SAID INNER TUBE SUSBTANTIALLY UPSTREAM OF SAID TERMINAL END THEREOF FOR INTRODUCING A SPRAY OF THE LIQUID TO BE DISPERSED INTO THE STREAM OF GAS FLOWING THROUGH SAID INNER TUBE. 